Hard-rubber composition.



UNITED STATES PATENT onnron LEO I-I. IBAEKELAND, or 'YONKERS, NEW YORK,assrenon T0 GENERAL BAKELITE COMPANY, OF NEW YORK, N. Y., A CORPORATIONOF NEW" YORK.

No Drawing.

vState of New York, have invented certain n'ewl and useful Improvementsin Hard- Rubber Compositions,-of which'the following is a-specification.

It is a well known fact among hard rubber manufacturers that in order toObtain good hard rubber compositions which may easily acquire a goodpolish there are special precautions which must be taken.- Ordinaryfilling materials such as are used for soft rubber goods cannot well beused. The addition of resinous matters such as shellac,

copal, etc., is excluded, not only because goods containing suchresinous addltlons lose the capacity of taking an easy pol1s h,

but because they are far. more sensitive to the action of heat. For'thatreason, if for:- noother, themanufacturers of high grade hard rubbergoods prefer to use as-a filling material finely ground hard rubberitself.

' The present invention relates to hard rubber compositionsand'processes for mak1ng-- the same, the object of the invention beingthe preparation of hard rubber compositions or goods which are capableof acquiring a polish, and which at the same time are more resistant toheat, solvents, and chemical and physical influences than ordinary hardrubeber. For this purpose, I prepare a compo- 1' sition-which inaddition to rubber contains a certain proportion of finfusible condensationproducts of phenols and formaldehyde.

i id a 'tlons, suitable filling materials,-

To these may be added in various-propon.

as faras is warranted by the condirubber substitutes, etc.', as isgenerally practised in the manufactureof rubber goods. 1

The present process. has the further advantage that under certainconditions it is possible to use so-calle'd reclaimed rubber.

The simplest mode of carrying out the-process is as follows: To therubber composition compounded 1n any usual or desired manner-is added asuitable proportion, for exampleabout an equal amount'by weight of theinsoluble in'fusible condensation product of phone and formaldehyde,prelimi nariiy reducedtoa Verv .-finepowder. The

. mixing is done in accor ance' with the usual methods used in rubbermanufacture, and

I Specification of Letters Patent.

H. BAEKELAND, 1

HARD-RUB ER COMPOSITION.

hardest material, but to-employ instead an intermediate product ofcondensation, which although solid when cooled softens slightly whenheated without entering into fusion, and is relatively brittle atordinary temperatures, and'for that reason can easily be Patented Oct.10, 1916. Application filed June 16,1910. Serial 1 567,222.

ground and reduced to very fine powder.

This powder is incorporated withvthe rubber mass as above described, andthe mass which process the heat will transform the intermediatecondensation product into the veryv hard final condensation. product;v

"Another manner of carrying out the in vention is as -follows: Thecondensation 1 product of phenols and formaldehyde, either 1 in'itsintermediate or in its final state of condensation, is finelypulverized, and this.

powderis thoroughly mixed with pulver- The 1pulverulent ized vulcanizedrubber.

mixture is now pressed in very. hot 1110165 5 until the particles cementtdgether, 'after 7 which the articles are released from the.

mold and if necessary submitted to" further hardening by longerapplication of heat,- with or without pressure, without the necessity ofusing a mold.

, Instead of uslng. infusible condensation products in their finalstate,the process may be so modified as to form such products in the rubber'from the initial products which are capable of engendering them.'- Forcx-' *ample, a mixture of about. one volume of phenol or itshomologues,,cresolfete, with two layers, the one heavier and" viscous oroily, and the-other-a supernatant layer consistin chiefly of water andsome. water- 'solub esubstances. The liquid may be evap-. i

orated order to eliminate the water contained' inthe ppperl'ayer, orthe'oily or -visclous liquid gmay z be withdrawn-"forfurtheruse, Theabove chemical. reaction works especially well. infpreseneoofiemallpropor- 70 then submitted to -vul'canization, during tions'of bases, asfor example about five per cent. of aqueous ammonia.

In whatever way the condensation product has been obtained, it can nowbe directly mixed with or incorporated in the rubber mass; or ifpreferred the condensation product. may be submitted to further heating,whereby it may be thickened even to the point where the mass, oncooling, sets to a brittle solid, which on further heating can betransformed into the final infusible product, or into an intermediatestate as above described. Whether the product prepared as aboveindicated be oily, viscous, pasty or solid at ordinary temperatures, itis suitable for, use in the process by mixing with rubber. The operationis facilitated by the employment of heat during the mixing process.

A decided solvent or swelling act on 7 which the li uid, oily 0r pastyproducts exercise on ru ber renders the incorporation with rubber, orwith a mixture of rubber and sulfur or other filling materials, veryeasy, so that a plastic mass, is readily obtained which can be submittedto the ordinary molding and vulcanizing operations as, practised in therubber industry.

Instead of using new rubber, very satisfactory-results are obtained withvulcanized rubber or so-cal led reclaimed rubber, orold rubber, all ofwhich are easily incorporated with the initial products of condensation.

The mixture is preferably prepared by means of heated rollers. Asuitable proportion of sulfur may be incorporated with the heated mass,and the whole submitted to molding and to the action of heat or of heatand pressure. V

A further modification of the process consists in mixing the mass in hotmixing devices, as for example heated rollers, until it becomes morepastyin consistence and until,

on cooling, it' sets to'ja substance which'can' be aidedjl to a beground-or pulverized. The mass is then cooled, comminuted, and thepowder pressed in hot holds, as above described, into the form of thedesired articles. However the certainextent by the addition process isconducted, it may of so-called catalytic agents, or condensing agents,as for example by the addition of small proportions of alkalis', bases,salts or acids. I ave also found that it is of considerable advantagethat during or after the mixing process the mass should be dried inorder to expel any water or other disturbing or mixtures of these thisprocess chemically equivalent thereto.

The expression condensation product of phenols and formaldehyde asemployed in the claims is intended to cover either the final infusiblecondensation product, or such partial condensation products, whetherinitial or intermediate, as are capable of transformation into saidfinal product.

I claim:.

l. A hard rubber composition containing an infusible condensationproduct of phenols and formaldehyde, rubber and sulfur.

2. A hardrubber composition containing an infusible condensation productof phenals and formaldehyde, rubber, sulfur and suitable fillingmaterials.

3. A plastic rubber composition containing vulcanized rubber and acondensation product of phenols and formaldehyde, said compositionadapted for transformation by heat into a hard rubber composition.

4. A plastic rubber compositibn containing vulcanized rubber, sulfur anda condensation product of phenols'and formaldehyde, said compositionadapted for transformation by heat into a hard rubber composition.

in presence of twowitnesses.

' LEO BAEKELAND.

. Witnesses:

R. H. WILLIAMS, GEO. D. Knr-PPEL.

Iii testimony whereof, I afiix my signature @orrections 200,692.-

It is hereby certified that in Letters Patent No.-"1,2o0,692, grantedOctobei 10, 1916, up'n the application of Leo H. Baekelarid, of Yenkers,New Yo'rkjfor an impro vement in Hard-RubberQomiiositiol s, errorsappear-in the printed speci- 4 fiationjrequiring coireetion as follows:Page 2, line 47, for the word holds read molds; same page, lines 8081',-ic1aim 2, for the word phenals read phenhls; and

that the said Letters. Patent should beread with these correctienstherein that the same may conform to the x eeord of the case in thePatent Oficea Signed and'sea led this 31st day of Oct 0ber,A. D., 1916.

R. F. WHITEHEAD, Atztt Uomm'iss'ionea of Patents.

[SEAL] Ol.1O6-22.

